Re: [time-nuts] Restoring GR 1120-AB Frequency Standard
Mike Monett wrote: [EMAIL PROTECTED] wrote: Phil, I didn't believe that the thermoswitch was the problem, at first, chiefly because of the simplicity of operation. Eventually, after checking wiring, a carbon resistor that is in series with the thermoswitch, and components around the inner oven control circuitry, I removed the thermoswitch to the bench. After hooking up to a ohmmeter and using a 60 watt light bulb as the heat source, I found that I could duplicate the a pulsating open / close as before. I first focused on the bulb leads and eventually completely removed the old leads and rebuilt each one and did all new soldering under magnification. The problem remains the same. I'm ready to move on at this point noting that this component failure has me stumped and that the fault is most likely internal to the thermoswitch (as strange as this seems). Years ago, when I first saw how internal temperature worked using the mercury thermometer switch, I remarked that it was one component that would never fail. HA! That statement came back to haunt me. Best, Russ I have been following this thread with some interest, as I expect to have similar equipment in the future. What is amazing is how you discovered the problem! Like you, I would not have believed a mercury switch could fail. But a quick search showed the contact can oxidize, and gave several patents aimed at solving the problem: 1. Reduction of oxides in a fluid-based switch - US Patent 7071432, 07/04/2006 Often, oxides may form within the switch and inhibit proper functioning of the switch. For example, the oxides may increase or decrease the surface tension of the liquid metal, which may increase or decrease the energy required for the switch to change state. Oxides can lead to poor switch performance, and even switch failure, because they lessen or prevent a switching fluid from wetting surfaces it is supposed to wet. Hmm... but capacitive sensing should still work well. Cheer, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Restoring GR 1120-AB Frequency Standard
When I was at the university I saw and worked on a thermostatic switch that used a standard mercury thermometer. The little thing that clipped on to the thermometer was the capacitor in an oscillator. The detector for opening and closing the relay was a high Q tuned circuit. I saw them regularly because I had to keep teaching lab instructors how to tune them up before each use. In a controlled environment it might be possible to optimize such a circuit for stable operation and tight control. My intuition tells me that 1 degree is about as fine a control as you could get unless you had a very narrow range thermometer with a small capillary. You might be able to convert the existing thermostat to capacitive sensing. That is apparently what Magnus is suggesting. Regards. Max. K 4 O D S. Email: [EMAIL PROTECTED] Transistor site http://www.funwithtransistors.net Vacuum tube site: http://www.funwithtubes.net Music site: http://www.maxsmusicplace.com To subscribe to the fun with tubes group send an email to, [EMAIL PROTECTED] - Original Message - From: Magnus Danielson [EMAIL PROTECTED] To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, August 21, 2008 12:00 PM Subject: Re: [time-nuts] Restoring GR 1120-AB Frequency Standard Mike Monett wrote: [EMAIL PROTECTED] wrote: Phil, I didn't believe that the thermoswitch was the problem, at first, chiefly because of the simplicity of operation. Eventually, after checking wiring, a carbon resistor that is in series with the thermoswitch, and components around the inner oven control circuitry, I removed the thermoswitch to the bench. After hooking up to a ohmmeter and using a 60 watt light bulb as the heat source, I found that I could duplicate the a pulsating open / close as before. I first focused on the bulb leads and eventually completely removed the old leads and rebuilt each one and did all new soldering under magnification. The problem remains the same. I'm ready to move on at this point noting that this component failure has me stumped and that the fault is most likely internal to the thermoswitch (as strange as this seems). Years ago, when I first saw how internal temperature worked using the mercury thermometer switch, I remarked that it was one component that would never fail. HA! That statement came back to haunt me. Best, Russ I have been following this thread with some interest, as I expect to have similar equipment in the future. What is amazing is how you discovered the problem! Like you, I would not have believed a mercury switch could fail. But a quick search showed the contact can oxidize, and gave several patents aimed at solving the problem: 1. Reduction of oxides in a fluid-based switch - US Patent 7071432, 07/04/2006 Often, oxides may form within the switch and inhibit proper functioning of the switch. For example, the oxides may increase or decrease the surface tension of the liquid metal, which may increase or decrease the energy required for the switch to change state. Oxides can lead to poor switch performance, and even switch failure, because they lessen or prevent a switching fluid from wetting surfaces it is supposed to wet. Hmm... but capacitive sensing should still work well. Cheer, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Restoring GR 1120-AB Frequency Standard
Max Robinson [EMAIL PROTECTED] wrote: When I was at the university I saw and worked on a thermostatic switch that used a standard mercury thermometer. The little thing that clipped on to the thermometer was the capacitor in an oscillator. The detector for opening and closing the relay was a high Q tuned circuit. I saw them regularly because I had to keep teaching lab instructors how to tune them up before each use. In a controlled environment it might be possible to optimize such a circuit for stable operation and tight control. My intuition tells me that 1 degree is about as fine a control as you could get unless you had a very narrow range thermometer with a small capillary. You might be able to convert the existing thermostat to capacitive sensing. That is apparently what Magnus is suggesting. Regards. Max. K 4 O D S. Optical might work better. Maybe use the lens and laser from an old CDROM. It might be fun getting it to focus on the mercury column through a round glass tube. Or maybe the glass wouldn't even pass the infrared. I got a bad burn once picking up an empty wine glass that was sitting beside a fireplace. But I understand new systems use a blue laser, which might work even better. I wonder what kind of temperature control it would give, and what the long-term drift might be. Sounds like a fun project. Regards, Mike Monett ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Introduction and a couple of requests
Hi, Name is Scott McGrath and I am a fellow time nut who in addition to playing with precise timing also plays with clocks!. My current collection of standards includes the following HP 105B HP 117A HP 5061A HP 5065A ( dead physics package unfortunately ) Austron 2100F (sold to me as a T but no internal standard so I am assuming a F) TrueTime DC-XL My requests Manual for the 5065A prefix 1840A I also need some replacement modules for a Tektronix 492A I have many spare modules for this except of course for the ones I need Manuals to Share which I will scan pre-production manual for the 5065A but it is much earlier than my current 5065A and a manual for the 117A which ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] New T-Bolt arrived
Hi Everybody; My new t-bolt just arrived from TAPR. I powered it up, connected the comm cable to the PC and it seems to be working like a CHAMP! I have two questions for the group. 1) Is there a satellite (SV) map program available to go along with TBoltMon? 2) Who do I thank at TAPR for this splendid little jewel and the great deal? Best regards, Bob K7hbg ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Restoring GR 1120-AB Frequency Standard
Hmmm. That sounds like something to be stored away for the day when my thermostat goes bad. Sounds like it would work. Regards. Max. K 4 O D S. Email: [EMAIL PROTECTED] Transistor site http://www.funwithtransistors.net Vacuum tube site: http://www.funwithtubes.net Music site: http://www.maxsmusicplace.com To subscribe to the fun with tubes group send an email to, [EMAIL PROTECTED] - Original Message - From: Mike Monett [EMAIL PROTECTED] To: time-nuts@febo.com Sent: Thursday, August 21, 2008 2:07 PM Subject: Re: [time-nuts] Restoring GR 1120-AB Frequency Standard Max Robinson [EMAIL PROTECTED] wrote: When I was at the university I saw and worked on a thermostatic switch that used a standard mercury thermometer. The little thing that clipped on to the thermometer was the capacitor in an oscillator. The detector for opening and closing the relay was a high Q tuned circuit. I saw them regularly because I had to keep teaching lab instructors how to tune them up before each use. In a controlled environment it might be possible to optimize such a circuit for stable operation and tight control. My intuition tells me that 1 degree is about as fine a control as you could get unless you had a very narrow range thermometer with a small capillary. You might be able to convert the existing thermostat to capacitive sensing. That is apparently what Magnus is suggesting. Regards. Max. K 4 O D S. Optical might work better. Maybe use the lens and laser from an old CDROM. It might be fun getting it to focus on the mercury column through a round glass tube. Or maybe the glass wouldn't even pass the infrared. I got a bad burn once picking up an empty wine glass that was sitting beside a fireplace. But I understand new systems use a blue laser, which might work even better. I wonder what kind of temperature control it would give, and what the long-term drift might be. Sounds like a fun project. Regards, Mike Monett ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Odetics 325 425: File recovery
Fellow clockers, I'm still picking up the pieces from a major FTP archive crash that lost me a considerable amount of data. Among the files lost was the .PDF manuals for the Odetics 325 and 425. The firmware files I can recover, as I still have the EPROMs in my original unit, but the manuals are not ones that I have backup copies for. If someone can either send those to me, or tell me where they can be downloaded, it would be much appreciated. Thanks. -=-=-=-=-=-=-=-=-=-=-=- Bruce Lane, Owner Head Hardware Heavy, Blue Feather Technologies -- http://www.bluefeathertech.com kyrrin (at) bluefeathertech do/t c=o=m Quid Malmborg in Plano... ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Restoring GR 1120-AB Frequency Standard
Max A capacitance bridge using a transformer would be a lot more stable than merely using the capacitance to vary the frequency of an LC oscillator. The advantage of a capacitive sensing technique over a light beam is that it has much simpler and potentially more stable mechanical system than when a the mercury colum interrupts a light beam. Unless of course on has the Mercury column move a moire grating or similar setup such as making the top of the mercury column a reflector in an interferometer system. Bruce ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Further FTP recovery
Along the lines of my earlier request... If anyone did any downloading from my site in the past year or so, I would greatly appreciate copies of what you downloaded so I can rebuild. I will happily reimburse any postage or media (blank CD-R's, etc.) costs. Thanks much. -=-=-=-=-=-=-=-=-=-=-=- Bruce Lane, Owner Head Hardware Heavy, Blue Feather Technologies -- http://www.bluefeathertech.com kyrrin (at) bluefeathertech do/t c=o=m Quid Malmborg in Plano... ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Odetics 325 425: File recovery
I'm still picking up the pieces from a major FTP archive crash that lost me a considerable amount of data. Disks are cheap. Many years ago, one of the guys I worked with pointed out to me/us that it was cheaper to buy more disks than it was to pay us at our normal sallary to figure out which bits should be saved. You can do a lot of handwaving in that area, but that's the general idea. My straw man for low cost backup is a USB disk. I'm thinking of a real rotating disk rather than the typical flash disk. The key idea is that after you pull the cable, your system can't trash the bits. That is neither software nor fat fingers will delete anything. It isn't perfect, but it's close and simple. Any interesting bits should be backed up multiple ways. If any time-nuts have bits that aren't (well) backed up, please contact me off line so we can work out some way to add another backup copy to the system. -- These are my opinions, not necessarily my employer's. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
